1. Field of the Invention
The present invention relates to a method of producing a piezoelectric actuator used in a transporting apparatus or the like.
2. Description of the Related Art
A transporting apparatus which includes a transporting roller and a drive motor which drives the transporting roller has been hitherto generally used for transporting a paper or the like to be recorded in a recording apparatus. However, in recent years, a technology for applying a piezoelectric actuator, having a piezoelectric element made of a ceramics material such as lead zirconate titanate (PZT), to a variety of usages has been studied, and in particular, a technology for transporting an object (transportation object) by utilizing a deformation which is developed when a voltage is applied to the piezoelectric element has been proposed. For example, Japanese Patent Application Laid-open Publication No. 2003-111456 describes a piezoelectric actuator which has a plurality of piezoelectric actuator elements each of which includes a substrate in the form of a plate, piezoelectric elements provided to both surfaces of the substrate respectively, and a plurality of electrodes formed on surfaces of the piezoelectric elements respectively. This piezoelectric actuator is structured such that a front tip portion of the substrate is caused to be deformed due to bending deformation of the piezoelectric element, and an object which is cylindrical or tubular in shape can be transported by being moved by a very small amount in a longitudinal direction of the object by a ciliary movement of a plurality of substrates arranged in a circumferential direction of the cylindrical or tubular object. However, this transporting apparatus is structured to transport an object which is mainly cylindrical or tubular in shape, and thus there is a restriction on the shape of the object which can be transported. Accordingly, it is difficult to use this piezoelectric actuator for transporting an object which has a shape other than the cylindrical or tubular shape, such as a paper.
In view of this situation, the inventor of the present application invented a piezoelectric actuator which is capable of transporting objects which have various shapes along a predetermined transportation plane, by a minute feed amount (U.S. patent application Ser. No. 11/235,313 filed on Sep. 27, 2005, published on Mar. 30, 2006 as US 2006/0066177 and corresponding to Japanese Patent Application No. JP 2004-278911). In the piezoelectric actuator, each of the actuator elements has a drive section (bent thin plate section) which projects in a direction orthogonal to a transporting plane, and a piezoelectric layer arranged in the drive section. The drive section has a contact section which makes contact with an object and two inclined sections extending from the contact section, and the piezoelectric layer, made of a ferroelectric substance such as lead zirconate titanate, is formed as two piezoelectric layers arranged in the two inclined sections respectively. When an electric field acts on the piezoelectric layer of the piezoelectric actuator, the piezoelectric layer is deformed to cause the inclined section to deform to be bent. The contact section between the two inclined sections is displaced by this bending deformation, thereby making it possible to transport the object by a minute feed amount.
When the piezoelectric actuator capable of realizing transportation by a minute feed amount is manufactured, it is necessary to form the drive sections of the actuator elements to be bent in a projecting manner, and to form piezoelectric layers in the two inclined sections respectively of each of the drive sections. However, with a conventional method of forming a piezoelectric layer entirely on the plate-shaped member and then processing the plate-shaped member so that the actuator elements are formed in a divided manner, it is difficult to form the actuator elements having a bent shape, and also disadvantageous in view of producing cost. Accordingly, there has been a demand for a method with which a piezoelectric actuator having such a structure can be produced more easily.